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Showing 1 to 20 of 28 for “"Cataclysmic variables"”.
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Eclipsing Cataclysmic Variables With TESS
Cataclysmic variables (CVs) are compact, interacting binary systems consisting of a white dwarf primary accreting material from an evolved main-sequence companion. Since its launch in 2018, the Transiting Exoplanet Survey Satellite (TESS) has delivered unprecedented, long-term photometric coverage …
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Polarimetry of magnetic cataclysmic variables
… of its performance. Extensive observations of cataclysmic variables with emphasis on the AM Her and DQ Her classes are then presented. After consideration of the basic principles involved in the development of an efficient and accurate polarimeter, a design using two super-achromatic retarders …
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Rapid oscillations in cataclysmic variables
… optical and X-ray light curves of more than 30 cataclysmic variables to date. The observational characteristics of these oscillations are reviewed, and current models discussed. To put the observations in context, a detailed review is given of the canonical model of cataclysmic variables and the …
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MeerKAT observations of novalike cataclysmic variables
… a systematic survey of eleven nearby novalike cataclysmic variables in the radio band, using the MeerKAT radio interferometer. Radio emission is detected from four out of the eleven systems: IM Eri, RW Sex, V3885 Sgr and V603 Aql. While RW Sex, V3885 Sgr and V603 Aql had been previously …
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Spectroscopic studies of magnetic cataclysmic variables
… systems. The results of four candidate magnetic cataclysmic variables, which were selected from the ROSAT Bright Survey, are also presented. Time resolved spectra are used for the dual purpose of conducting Doppler tomographical studies and searching for any evidence of cyclotron beaming. The …
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Accretion disks in the cataclysmic variables
The general equations describing the time-independent structure of gaseous circumstellar disks in vertical hydrostatic equilibrium are derived. The possibility of turbulent instablilty and the resulting viscosity laws are discussed.
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Observational studies of highly evolved cataclysmic variables
Cataclysmic Variables (CV) are binary systems where a main-sequence star transfers mass onto a white dwarf (WD). According to standard evolutionary theory, angular momentum loss drives CVs to initially evolve from longer to shorter orbital periods until a minimum period is reached (? 80 minutes). …
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Characterisation of the Components in Cataclysmic Variables
… X-ray, optical and ultraviolet observations of cataclysmic variables, and discusses the results obtained in the context of the relationship between the physical and spectral components visible. It concentrates on the eclipsing dwarf nova OY Carinae, which has been observed both in superoutburst …
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Theoretical statistics of zero-age cataclysmic variables
… and the distribution of the orbital periods in cataclysmic variables which are forming at the present time are calculated. These systems are referred to as ""zero-age cataclysmic variables"". The results show that 60% of the systems being formed contain helium white dwarfs and 40% contain …
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Studies of an x-ray selected sample of cataclysmic variables
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1992
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Transforming Doppler tomography to unravel the accretion dynamics in cataclysmic variables
… and inside-out Doppler tomography of magnetic cataclysmic variables. I developed this technique with the aim to obtain more information from their observed spectra and present it in a useful format. It extracts the flux modulation from consecutive half-phase tomograms and constructs maps of the …
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Accretion processes in magnetic cataclysmic variables - a detailed study of UZ Fornacis
… exploration of the emissions from magnetic cataclysmic variable (mCV) stars with specific focus on the eclipsing AM Her system, UZ Fornacis (hereafter UZ For). The main objective of this thesis is to investigate the underlying emission mechanisms as well as the accretion dynamics in this …
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A survey of cataclysmic variables from the Edinburgh-Cape Blue object survey
… and follow-up photometry and spectroscopy of the cataclysmic variable stars (GVs) found by the survey. Because of the north-south imbalance in the number of blue objects, the Edinburgh-Gape Blue Object survey was designed to discover previously unknown blue objects with B≤~18 at high galactic …
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Exploring the application of new telescope technologies in the testing of dwarf novae accretion models
… demonstrate, within the context of accretion in cataclysmic variables (CVs), their role in contributing to the stellar variability studies which help drive their development.
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Superhumps in AM Canum Venaticorum stars
… are observed in non-magnetic (hydrogen-rich) cataclysmic variables. Five of the six systems show low-amplitude optical oscillations with periods between 500 and 2000 s. The oscillations have a complex and variable harmonic structure. Since they are consistent with the predictions of the …
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Magnetohydrodynamical phenomena in gaseous disks
… here is on application to accretion disks in the cataclysmic variables (CVs). These include novae, dwarf novae and nova-like variables. Disks are maintained by mass transferred from a Roche-lobe filling secondary star to a white dwarf. More information can be found in Warner (1976) and Robinson …
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The gravity oscillations of white dwarf stars
… the discovery of periodic variations in several cataclysmic variables. Its completion within a reasonable time was greatly helped by the availability of a computer program for the solution of the equations governing the structure of white dwarf stars provided by Dr W. B. Hubbard. Although the …
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Machine learning from hard x-ray surveys: applications to magnetic cataclysmic variable studies
… astronomy whilst the second is that of magnetic cataclysmic variables (mCVs). To begin, an overview is given of ISINA: INTEGRAL Source Identification Network Algorithm. This machine learning algorithm, using random forests, is applied to the IBIS/ISGRI data set in order to ease the production of …
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Pulsations in the white dwarf primary of a cataclysmic variable star
… could be applied to the white dwarf primaries of Cataclysmic Variable stars, the study of accretion in interacting binary systems would benefit enormously. Our understanding of normal modes in white dwarf pulsators would benefit likewise from the study of how they respond to accretion. This …
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Physics in the extreme: X-ray and optical studies of magnetic white dwarfs and related objects
… - mainly periods and inclinations for several cataclysmic variables - and examine the accretion structures within the systems. In Chapters 3 and 4, optical and X-ray studies of two interesting cataclysmic variables systems, Lanning 386 and MASTER OTJ192328.22+612413.5, are presented. The X-ray …
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